Interfacial energy barrier height of Al_2O_3/H-terminated (111) diamond heterointerface investigated by X-ray photoelectron spectroscopy

摘要

The interfacial band configuration of the high-κ dielectric Al_2O_3 deposited at 120 °C by atomic layer deposition (ALD) on boron- and phosphorus-doped hydrogen-terminated (111) diamond was investigated. Performing X-ray photoelectron spectroscopy measurements of core level binding energies and valence band maxima values, the valence band offsets of both heterojunctions are found to be ΔE_V = 1.8 eV and ΔE_V = 2.7 eV for Al_2O_3/H(111)p and Al_2O_3/H(111)n, respectively. The ALD Al_2O_3 bandgap energy was measured from the O 1s photoelectron energy loss spectra to be EGAl2O3=7.1 eV. The interfacial band diagram configuration is found to be of type II for both Al_2O_3/H(111)p and Al_2O_3/H(111)n heterostructures having conduction band offsets of ΔE_C = 0.2 eV and ΔE_C = 1.1 eV, respectively. The use of doped (111) hydrogen-terminated diamond for developing future diamond metal-oxide-semiconductor field-effect transistors is discussed.